Ethan Nadelmann and Stephen Colbert on Drugs

Last night was an end of an era. After nine years on the air, Stephen Colbert is stepping away from his award winning show, The Colbert Report.

Like millions of others, I tuned in regularly to get the news of the day from the hilarious show. I loved how the show could educate people and explain complicated issues in such an entertaining way.

The segments were often more informative than networking news, and a hell of a lot funnier.

Ethan Nadelmann, the executive director of the Drug Policy Alliance, had the honor of going on his show three times. I've seen Ethan do interviews on many shows, from CNN's Fareed Zakaria, to the O'Reilly Show to the Lehrer News Hour, but I was always most excited when Ethan would go on Colbert's show.

My favorite clip of Ethan and Colbert is from 2009. In this short segment, Ethan was able to make important points about the disastrous war on drugs -- from the violence that has taken tens of thousands of lives in Mexico, to the millions arrested every year in the US because of drugs, to the parallels between failed alcohol prohibition and today's drug prohibition.

Ethan showed his own sense of humor when Colbert asked Ethan during his interview if he ever used drugs. Without missing a beat, Ethan said, "I've smoked the occasional joint when I watch you, but never when I'm on you."

The crowd cheered and Stephen looked at a loss for words. A few seconds later, Colbert said smiling, "You mean on my show right?"

It's worth noting that when Ethan spoke about the support for marijuana legalization, at that time he said close to 40 percent of Americans supported it.

That was in 2009.

Five years later the support for legalization is over 50 percent. Four states and D.C. have legalized marijuana for adult use.

That is incredible progress in just five years. And I would argue, that Colbert and his show helped build some of that support.

Thanks for the laughs and the lessons, Mr. Colbert.

Tony Newman is the director of media relations at the Drug Policy Alliance.

This piece first appeared on the Drug Policy Alliance Blog.